Variability of non-breaking surface-wave induced mixing and its effects on ocean thermodynamical structure in the northwest Pacific during Typhoon Lekima (2019)

Abstract

The surface waves, which contain most of the mechanical energy in the upper ocean, greatly contribute to the vertical mixing processes. Two of the non-breaking wave-induced physical processes, including wave-generated turbulence and residue of wave transport flux, are introduced as two mixing schemes, and incorporated into the ocean circulation model to study the effects on the upper ocean during the Typhoon Lekima (2019). The new vertical diffusion terms, corresponding to the wave-induced mixing processes, can be calculated directly based on the simulated surface wave parameters from wave spectrum model. Four numerical experiments are designed for analysis and comparison of the temperature and current in the upper ocean. The results show definite improvement in the sea surface temperature cooling, the upper-ocean thermal structure and mixed layer depths when the two schemes are adopted, because the upper-ocean vertical mixing processes are enhanced. The surface waves can especially strengthen the contribution of the vertical diffusion terms to the temperature cooling during the typhoon period.